Kalkwasser

[A.Percula]

I know this has been discussed a lot . But I have tried several ways to increase pH in my tank and they just don’t work. (Co2 scrubber, refugium, increased water movement) and nothing works.

Kalkwasser seems to do the trick, but since its on the ATO, its inconsistent and water evaporations depends on when AC is on or off. I’ve seems spikes of pH by .10 when ATO turns on. Is this too much? Should I reduce the amount of Kalkwasser? Should I get a slower pump?

When I say low pH I am saying 7.50 in the morning. Sometimes 7.4.

 

[Randy Holmes-Farley]

I don’t think a change in pH of 0.1 had been shown to be an issue.

The kalkwasser or an equally high pH two part can be put on a dosing pump if you prefer.

 

[A.Percula]

thanks. What are some of the high pH additives? And how much of a jump is considered risky, .50?

 

[dwest]

Sodium carbonate or “soda ash” is a common alkalinity replacement in 2 part that has a high pH. There is also a sodium hydroxide version that I have never tried.

I would consider at 0.5 pH unit quick rise as too much.

New DIY Two Part Recipes with Higher pH Boost

Here's a first crack at what may end up being multiple possible recipes for a DIY two part that either has a higher pH or can be made more concentrated than traditional two part recipes. This one has about twice the pH raising effect compared to a carbonate based two part, per unit of...

www.reef2reef.com

 

[Randy Holmes-Farley]

thanks. What are some of the high pH additives? And how much of a jump is considered risky, .50?

You can make a two part with sodium hydroxide that has equal pH raising per unit of alk as does limewater (kalkwasser):

Second New DIY Two Part Recipe with Higher pH Boost

In a previous thread, I posted a true two part DIY recipe: https://www.reef2reef.com/threads/new-diy-two-part-recipes-with-higher-ph-boost.344500/ But some folks may want to just swap the new ingredient into my 2/3 part recipe (as used by BRS, for example). Here's the original recipe link...

www.reef2reef.com

How much is OK may depend on the starting pH. I wouldn't prefer to see more than 0.2 pH units, but that's an opinion without much supporting evidence.

 

[blasterman]

Kalk in an ATO is supposed to temper the pH drop of adding R/O or distilled fresh water to a tank. In that role I find it a bit of a pain because it's one more thing to mix and monitor and if your dosing pump ever fouls up an over dose of kalk really screws things up. You need to, IMO, have a lot of top off via volume to make it worth it and have a need for a pH boost for kalk in the first place. The calcium and alk boost kalk provides is nice, but kind of trivial if your tank consumes a fair amount of either.

One suggestion is to only run top offs with kalk at night when you typically need the pH boost.

I've manually added kalk on some stubborn tanks during the winter when I can't get enough fresh air. Just like baking soda dosing I fill some tank water in a quart juice jug, add the kalk, shake it for a few minutes, then add it back. up to 1/2 teaspoon per 10 gallons has never given me issues. Above that and it seems precipitation starts to creep in. I've seen some nasty kalk induced precipitation events in my career and it takes a pretty severe pH jump to bug corals. Dropping pH is more of an issue for SPS.

I really have to question a pH reading of 7.4 because the only times I've seen pH legitimately that low is when a reactor isn't tuned right and dumping too much Co2 in the tank.

 

[Crustaceon]

I know you said you tried everything, but have you tried hooking up a hose to your skimmer inlet and routing it outside?

 

[splitting_lanes]

I‘m dosing kalk with a litermeter and it works out great. Real consistent 8.3 ph and Alk/cal numbers.

 

[Randy Holmes-Farley]

Kalk in an ATO is supposed to temper the pH drop of adding R/O or distilled fresh water to a tank.

FWIW, that is chemically incorrect. People may think it, but then they are doing a reasonable thing for a wrong reason.

Adding totally pure fresh water at pH 7.0 to tank water at pH 8.0 results in a pH rise, not a drop. Counter intuitive, but true. There is no need to temper anything. It is just a convenient way to dose calcium and alkalinity, and raise pH as well.

I show why here:

Master Reef Chemist Certification Question!!! (yes, you want this title)

Let's have some fun with a question that wraps up several different aspects of reef chemistry into a single, very simple (perhaps deceptively simple) question. It's just the pH of a hyposalinity solution. How much easier can it get? [emoji1] Get it right for the right reason and you too can...

www.reef2reef.com

 

[Randy Holmes-Farley]

I really have to question a pH reading of 7.4 because the only times I've seen pH legitimately that low is when a reactor isn't tuned right and dumping too much Co2 in the tank.

I agree that pH 7.4-7.5 is almost certainly test error.

 

[A.Percula]

I agree that pH 7.4-7.5 is almost certainly test error.

I tested with Hanna pH probe and now with Apex (both calibrated with two point solution). That’s why I got scared, I thought it was a test error two, but Apex then showed same results.

 

[The Opinionated Reefer]

Surly a CO2 scrubber attached to your skimmer in recirculating way would have some effect on raising pH? I have just ordered one of these myself as I get a large pH swing from day to night.